Fuel, Fire, but No Start: Inside a Rodeo’s Silent Kill Switch

Allan Burlace
11 minutes ago
2 min read

The Rodeo That Died Mid-Drive — One Solenoid to Blame

By Allan Burlace — Agnews Auto Services

Vehicle

2003 Holden Rodeo 3.0L 4JH1-T, Electronically controlled mechanical diesel injection — not common rail. Towed in after an unexpected shutdown on the highway.

Complaint

“It just died while I was driving. No warning. Cranks but won’t start.”

Step 1 – Confirm the Fault

Customer phoned it in. I picked it up in the tow truck and brought it back to the shop.Naturally, I tried to start it — no go. Cranked strong, but no signs of firing.

Primer was firm = system primed ✅
Removed feed line to pump = fuel present ✅
Cracked injector line at pump = no fuel delivery ❌

Right there I knew we had an electrical or control issue — not a fuel supply problem.

Step 2 – Understand the System

Pulled the wiring diagram from Autodata.This isn’t a basic old-school diesel with a single fuel cut wire — the injection pump on the 4JH1 has a multi-pin plug with:

IGN power
ECU-controlled fuel cut solenoid
Ground
Signal/sensor lines (likely advance or metering feedback)

So I traced it out wire by wire.

Step 3 – Load-Test Every Pin

Using a multimeter and test light:

Main IGN power confirmed at the heavy blue/red wire ✅
Ground checked with a test light to battery positive — solid ✅
Sensor wires both showed ~2.5V KOEO — signal present ✅
That left Pin 5 (orange) — the fuel cut solenoid control wire

Step 4 – Voltage vs Current Test

With pump unplugged, I back-probed Pin 5:

Saw 12V KOEO — looked good
Plugged the pump in = voltage dropped to 0.3V
Tried a low-draw test light with the plug removed — voltage vanished completely but the light did not light. The driver in the ecu could not even power my test light.

That’s textbook ECU driver collapse under load. No current delivery = no solenoid activation = no fuel.

Step 5 – What Killed the Driver?

I tested resistance between Pin 5 and ground (pump side only):

1.7 ohms, that's low resistance!

That’s a dead short in ECU terms. At 12V, it’s trying to push over 7 amps into a circuit designed for 1–2A max.No wonder the ECU driver fried.

Conclusion

Shorted fuel cut solenoid killed the ECU driver
That shut the engine down mid-drive — hard fault, not a random glitch
ECU now fails to power the solenoid even under light load

Fix

Ideally it is a pump out job and a replacement ECU, that will need to be programmed in I assume.

Takeaway

You don’t guess your way through faults like this. It really looked like an ECU fault, had we just replaced the ECU it would have fried straight away. You trace, you test under load, and you follow the current.

Voltage alone means nothing — current under load tells the truth.

That’s how we do it at Agnews.